I. Field
The following relates generally to wireless communication, and more specifically to identifying and correcting timing errors in wireless communication signals.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content and services such as, e.g., voice content, data content, video content, packet data services, broadcast services, messaging services, multimedia services, and so on. Typical wireless communication systems can be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access systems can include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations can be established via a single-in-single-out (SISO) system, a multiple-in-single-out (MISO) system, or a multiple-in-multiple-out (MIMO) system.
One aspect of providing reliable data exchange in wireless environments involves coordinating signal timing among remote transceivers. Because multiple-access communication systems involve concurrent transmissions, interference between transmitters can result. To counter wireless interference, signals are segmented into different resources, some resources employing different time slots, some resources employing orthogonal frequency bands or orthogonal spreading codes, and so on. In order for time division to be effective, however, transmitting and receiving devices typically must be synchronized in time. As an example, data scheduled for transmission in a particular time slot is expected to be received at a particular point in time by a receiver. If the receiver does not obtain the data when expected, an error might result in identifying the data from a transmission schedule (resulting in packet loss).
To mitigate timing problems, transceivers typically employ a default timing sequence(s) to synchronize remote devices in time. Signal transmission and responses to transmission are compared to the default timing sequence to identify time-based deviations in round-trip signaling. Based on the comparison, identified deviations in signal timing can be corrected.
Various mechanisms can be employed to analyze wireless signals and identify timing deviations. One mechanism is to analyze a particular wireless channel (e.g., predetermined set of signal resources), such as a reference signal, that is transmitted repeatedly by a wireless transceiver (e.g., base station, access point, relay, repeater, or the like). Thus, for instance, each time the reference signal is transmitted, a response to the reference signal is analyzed and timing compared with the default timing sequence. Errors can result with reference signal analysis, however, as with other analysis. Because timing errors can result in packet loss, which adds overhead and increases processing and power consumption, a goal of ongoing research in wireless communications is to reduce likelihood of timing errors in existing and future systems.